Tuning precise numbers of supported nickel clusters on graphdiyne for efficient CO2 electroreduction toward various multi-carbon products

Compared to single-atom catalysts, supported metal clusters can exhibit enhanced activity and designated selectivity in heterogeneous catalysis due to their unique geometric and electronic features. Herein, by means of comprehensive density functional theory (DFT) computations, we systematically investigated the potential of several Ni clusters supported on graphdiyne (Nix/GDY, x = 1–6) for CO2 reduction reaction (CO2RR). Our results revealed that, due to the strong interaction between Ni atoms and sp-hybridized C atoms, these supported Ni clusters on GDY exhibit high stabilities and excellent electronic properties. In particular, according to the computed free energy profiles for CO2RR on these Nix/GDY systems, the anchored Ni4 cluster was revealed to exhibit high CO2RR catalytic activity with a small limiting potential and moderate kinetic barrier for C–C coupling, and CH4, C2H5OH, and C3H7OH were identified as the main products, which can be attributed to its strong capacity for CO2 activation due to its unique configuration and excellent electronic properties. Thus, by carefully controlling the precise numbers of atoms in sub-nano clusters, the spatially confined Ni clusters can perform as promising CO2RR catalysts with high-efficiency and high-selectivity, which may provide a useful guidance to further develop novel and low-cost metal clusters-based catalysts for sustain CO2 conversion to valuable chemicals and fuels.